Extreme ultraviolet radiation of transient plasma in fast conical discharge

: The article presents the results of the detailed experimental study of fast conical discharge with Ar as a working gas. The discharge produces a compact transient plasma which emits extreme ultraviolet (EUV) radiation with wavelength 10.8 nm. The intensity of this spectral line is an order of magnitude larger than the rest of the radiation in EUV band. Space resolved EUV spectra allowed us to get the estimation of the effective size of the radiation source (less than 0.5 mm). Time resolved spectra (frame time 20 ns) show that a 10.8-nm spectral line is emitted during 50-60 ns. Charge exchange of Ar IX ions with excited atoms of Ar I in the result of interaction of hot compact plasma in the cumulation point of conical shockwave and cold working gas is considered as the main phenomenon, responsible for the emission of the detected radiation.